How to disable recent email address list from showing up when composing a new email message?

So, my grandparents got an iPad Air for Christmas. I associated it with our family Apple ID and thought that everything is going to work well. Then we wanted to send some emails, after I set up their email account. When we wrote something in the adrese row, iPad gave us a list of recently used contacts, tha some members of my family already used. They don't have any contacts in the contact app, if I click the information button next to the recent email adress it only says that it is recent and there is an option to delete from recent. Does anyone know how do I turn this off? Or should I get them their own account and hook it up with family sharing? Thanks a lot for the answers! 😊